Bottom Line:
Secondary outcomes were the effect by age group (16-29, 30-49, and ≥ 50 years) and by UK constituent country.The greatest effects may occur in young people, with no significant differences between income groups.Both effects warrant further exploration.

Affiliation: British Heart Foundation Health Promotion Research Group, Nuffield Department of Population Health, University of Oxford, Oxford OX3 7LF, UK.

ABSTRACT

Objective: To model the overall and income specific effect of a 20% tax on sugar sweetened drinks on the prevalence of overweight and obesity in the UK.

Design: Econometric and comparative risk assessment modelling study.

Setting: United Kingdom.

Population: Adults aged 16 and over.

Intervention: A 20% tax on sugar sweetened drinks.

Main outcome measures: The primary outcomes were the overall and income specific changes in the number and percentage of overweight (body mass index ≥ 25) and obese (≥ 30) adults in the UK following the implementation of the tax. Secondary outcomes were the effect by age group (16-29, 30-49, and ≥ 50 years) and by UK constituent country. The revenue generated from the tax and the income specific changes in weekly expenditure on drinks were also estimated.

Results: A 20% tax on sugar sweetened drinks was estimated to reduce the number of obese adults in the UK by 1.3% (95% credible interval 0.8% to 1.7%) or 180,000 (110,000 to 247,000) people and the number who are overweight by 0.9% (0.6% to 1.1%) or 285,000 (201,000 to 364,000) people. The predicted reductions in prevalence of obesity for income thirds 1 (lowest income), 2, and 3 (highest income) were 1.3% (0.3% to 2.0%), 0.9% (0.1% to 1.6%), and 2.1% (1.3% to 2.9%). The effect on obesity declined with age. Predicted annual revenue was £276m (£272m to £279m), with estimated increases in total expenditure on drinks for income thirds 1, 2, and 3 of 2.1% (1.4% to 3.0%), 1.7% (1.2% to 2.2%), and 0.8% (0.4% to 1.2%).

Conclusions: A 20% tax on sugar sweetened drinks would lead to a reduction in the prevalence of obesity in the UK of 1.3% (around 180,000 people). The greatest effects may occur in young people, with no significant differences between income groups. Both effects warrant further exploration. Taxation of sugar sweetened drinks is a promising population measure to target population obesity, particularly among younger adults.

Mentions:
We aggregated the Living Costs and Food Survey drinks groups into groups as set out in figure 2 for the purposes of simulating the effects of a sugar sweetened drink tax. However, estimating a single demand system for these groups was not possible. We therefore adopted the hierarchical approach depicted in figure 2 and estimated five demand systems. The elasticities that result from this estimation are conditional and assume that the change in quantity resulting from a change in price takes place with expenditure on all of the goods in the given demand system remaining constant. To relax this assumption, we calculated unconditional elasticities.37 Unconditional elasticities allow expenditure on a group to change in response to a price change within that group. They allow, for example, an increase in expenditure on sugar sweetened drinks in response to a rise in their price that is offset by reducing expenditure on another food or drinks group.

Mentions:
We aggregated the Living Costs and Food Survey drinks groups into groups as set out in figure 2 for the purposes of simulating the effects of a sugar sweetened drink tax. However, estimating a single demand system for these groups was not possible. We therefore adopted the hierarchical approach depicted in figure 2 and estimated five demand systems. The elasticities that result from this estimation are conditional and assume that the change in quantity resulting from a change in price takes place with expenditure on all of the goods in the given demand system remaining constant. To relax this assumption, we calculated unconditional elasticities.37 Unconditional elasticities allow expenditure on a group to change in response to a price change within that group. They allow, for example, an increase in expenditure on sugar sweetened drinks in response to a rise in their price that is offset by reducing expenditure on another food or drinks group.

Bottom Line:
Secondary outcomes were the effect by age group (16-29, 30-49, and ≥ 50 years) and by UK constituent country.The greatest effects may occur in young people, with no significant differences between income groups.Both effects warrant further exploration.

Affiliation:
British Heart Foundation Health Promotion Research Group, Nuffield Department of Population Health, University of Oxford, Oxford OX3 7LF, UK.

ABSTRACT

Objective: To model the overall and income specific effect of a 20% tax on sugar sweetened drinks on the prevalence of overweight and obesity in the UK.

Design: Econometric and comparative risk assessment modelling study.

Setting: United Kingdom.

Population: Adults aged 16 and over.

Intervention: A 20% tax on sugar sweetened drinks.

Main outcome measures: The primary outcomes were the overall and income specific changes in the number and percentage of overweight (body mass index ≥ 25) and obese (≥ 30) adults in the UK following the implementation of the tax. Secondary outcomes were the effect by age group (16-29, 30-49, and ≥ 50 years) and by UK constituent country. The revenue generated from the tax and the income specific changes in weekly expenditure on drinks were also estimated.

Results: A 20% tax on sugar sweetened drinks was estimated to reduce the number of obese adults in the UK by 1.3% (95% credible interval 0.8% to 1.7%) or 180,000 (110,000 to 247,000) people and the number who are overweight by 0.9% (0.6% to 1.1%) or 285,000 (201,000 to 364,000) people. The predicted reductions in prevalence of obesity for income thirds 1 (lowest income), 2, and 3 (highest income) were 1.3% (0.3% to 2.0%), 0.9% (0.1% to 1.6%), and 2.1% (1.3% to 2.9%). The effect on obesity declined with age. Predicted annual revenue was £276m (£272m to £279m), with estimated increases in total expenditure on drinks for income thirds 1, 2, and 3 of 2.1% (1.4% to 3.0%), 1.7% (1.2% to 2.2%), and 0.8% (0.4% to 1.2%).

Conclusions: A 20% tax on sugar sweetened drinks would lead to a reduction in the prevalence of obesity in the UK of 1.3% (around 180,000 people). The greatest effects may occur in young people, with no significant differences between income groups. Both effects warrant further exploration. Taxation of sugar sweetened drinks is a promising population measure to target population obesity, particularly among younger adults.